def main():
  while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
      
if __name__ == "__main__":
  main() def main():
  while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
       main while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
       True s = input() s input() input degree = int(s) degree int(s) int s if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
       degree >= 30 degree 30 print("Yes") print "Yes" break print("No") print "No" break if __name__ == "__main__":
  main() __name__ == "__main__" __name__ "__main__" main() main def main():
  while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
       def main():
  while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
       main
def main():
  while True:
    s = input()
    degree = int(s)
    if degree >= 30:
      print("Yes")
      break
    else:
      print("No")
      break
      
if __name__ == "__main__":
  main()